Mewtwo is a modified clone of the Pokemon Mew. The scientists who created it dreamed of making the strongest Pokémon ever that in return destroyed it creators. So far in the anime and mangas there has been only one in existence.

Unlike what most people tend to believe Pidgeot is not based on a bird of prey, at least not for the most part. No its based on a Pigeon. Having evolved from Pidgey and Pidgeotto this is now big and strong enough to carry a adult sized human.